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(No Model.) 3 Sheets-Sheet 1.

E. P. COWLES. OUT-OFF MECHANISM FOR STEAM ENGINES. No. 470,863. PatentedMar. 15, 1892.

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3 Shets-Sheet 2.

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E. P. OOWLES. OUT-OFF MECHANISM FOR STEAM ENGINES.

Patented. Mar. 15, 1892.

WITNESSES:

NORRIS FEYEIS co., moroan'nm, wwnmuwn, 0. c4

(No' Model.) a Sheets-Sheet 3. E. OOWLES. GUT-OFF MECHANISM FOR STEAMENGINES.

PatentedM ar. 15, 1892.

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was en, Prim-011mm, WASHINGTON n c luv-11 EDNVARD P. COVVLES, OF NEWVDECATUR, ALABAMA.

CUT-OFF MECHANISM FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 470,863, dated March15, 1892. Application filed August 1'7, 1891. Serial No. 402,797. (Nomodel.)

- To aZZ whom it may concern.-

Be it known that I, EDWARD P. OOWLES, a citizen of the United States,residing at New Decatur, in the county of Morgan and State of Alabama,have invented certain new and useful Improvements in Out-Off Mechanismfor Steam-Engines, of which the following is a specification. I

This invention relates to an improvement in cut-off mechanism forsteam-engines. It

is herein illustrated as applied to the style of compound engine shownand described in an application for patent, Serial No. 376,940, filed byme January 7, 1891, but is also applicable to other forms of engines.

The invention is illustrated in the accom panying drawings,in WhichFigure 1 shows a side elevation of the engine provided with my improvedcut-off mech anism. Fig. 2 shows atop or plan view with parts brokenaway and parts shown in section. Fig. 3 is an enlarged sideyiew of thecut-off mechanism. Fig. 4 is an end view of the same. Fig. 5 is atransverse vertical section on the line 5 5 of Fig. 2. Fig. 6 is anenlarged detail sectional view illustrating the construction of thecut-off valves and ports. Fig. 7 is a diagram representing the relativemovements of the piston and valves in double expansion. Figs. 8 and 9are detail views showing my improved cut-off applied to commonslide-valves.

As before stated, my invention is herein shown applied to a compoundengine of the type described in my former application. In this enginethe steam-chests 5 are located at opposite ends of the cylinder 11, andin them work the two slide-valves 32, which are suitably connectedtogether, so that they operate as one valve. Bolted to the flange of therear valve is a rearwardly-extending yoke or saddle 50, to which aresecured rearwardly-extending hollow stems 51, which are locatedonopposite sides of the piston rod 15, and are formed with forked endswhich have grooves in their extremities, as shown at47. (See Fig. 2.)Through these stems pass rods 52, which are attached to and work acut-off valve 53, which, together with the openings or ports it closes,are shown in detail in Fig. 6. These rods are also provided withbifurcated ends 48, the purpose of which will be hereinafter stated.

At the rear end of the rear valve 32 is, as shown in Fig. 2, a wallperpendicular to the line of travel of said valve, and within this wallare formed the annular openings 54, which admit steam to the inside ofthe valve and leave bars 55. The cut-off valve is of the same form asthis wall, and its bars correspond with and serve to close the openingsor steam-ports between the bars of the said wall. At the forward end ofthe forward valve is a similar wall and cut-off valve, and the cut-offvalves are connected together by means of rods 59, which are secured toradial arms 58, connecting together the bars of the cut-off valves andextending beyond the slide-valves to permit their connection with therods 59, thus forming practically one valve. These rods are ofsufficient length to allow play be tween the cut-off valves and theopen'wallsof the slide-valves. alternately to open and close the ports,or, in other words, when the cut-off ports at one end of the engine areopen those at the other end thereof are closed.

The slide and cut-oft valves are operated by the following-describedmechanism: 40 designates a rock-shaft, which is operated by means of thearm 44 and eccentric-rod 45,'located outside of the bed-plate, as isusual. This rock-shaft is provided with depending arms 46, which arelocated in pairs on opposite sides of the piston-rod 15, as shown inFig. 5. The lower ends of these arms are pivoted to the forkedends 47 ofthe hollow stems 51. The rock-shaft is cast hollow, and through itpasses a shaft 60, which is provided with depending arms 61, locatedbetween the arms 46 of the rock-shaft, and pivoted at their lower endsto the rear extremities of the rods 52, which rods are, as hereinbeforestated, formed .or provided with bifurcated rear extremities for thereception of the ends of said arms. The shaft is also provided with anarm 62, which extends parallel with the arm 44 of the rock-shaft and,like said arm, is located be yond the outer surface of the bed-plate ofthe engine. From the foregoing it will be readily understood that anymovement of the arm 62 with respect to the arm 44 will move the cut- Thecut-off valves operate off valve 53 with respect to the slide-valve 32within the rear steam-chest, and that when said rods move together or inunison no such movement of the cut-oif valve will result.

In view of the fact that with the above-described construction there isno room for the usual connection between the stems 51 and rods 52 andthe arms 46 and 61, and that it is necessary to accommodate the aredescribed by said arms in operation, the rock-shaft is supported invertically-movtble bearings 63 by arms 64, the said bearings sliding inbrackets 65 on the engine-frame.

The mechanism for operating the cut-off valves is supported by a blockor frame 70, (see Figs. 3 and 4,) which is movable in guides 71, formedon a bracket 7 2,.attached to the engine-frame. This block is connectedto the arm 44 of the rock-shaft by means of a rod 73, so that inoperation it has the same horizontal movement as the eccentric-rod 45.

74 designates an eccentric crank or cam, which is provided with a pin75, forming its axle. This pin has its hearings in the block or frame70, and it extends outward therefrom toward the eccentric-rod 45. Anymovements of the eccentric crank or cam 74 will be transmitted to thecut-off valves by a rod 84, connecting said eccentric and the arm 62,moving said valves with respect to the slidevalves 32 and opening orclosing the ports in the walls of said slide valves as the horizontalmotion of the pin 75 coincides with that of the pivot-pin 7 6 of the arm44; but when said eccentric is stationaryitwillfirmly resist any motionof said cut-off valve with respect to the slide-valve.

The eccentric -cam 74 is formed or provided with a hub 77, which inshape is like a frustum of a cone, and located outside of this hub andcentered on the pin 75 thereof is a pinion or segment of a pinion 78,the inner surface of which is cupped to fit said coneshapcd hub. Aspring 200, Fig. 2, is located outside the pinion 78, which spring, whencompressed by a nut on the end of the pivot-pin 75, will force the conestogether and both against the block or frame 70. The friction betweenthe cones is greater than that between the eccentric-cam and the blockor frame, and thus when the pinion 78 turns it will carry theeccentric-cam and also the cutoff valve with it until said cutoff valveis seated, when further movement of said eccentric-cam ceases and thecones slip the rest of the movement of the pinion or segment of apinion. It will therefore be seen that the initial movement of thepinion in either direction opens or closes the cut-oif, and that thebalance of its movement is consumed by the slip-joint formed by the hubof the eccentrica crank and the cup of the pinion.

Intermeshing with the teeth of the segment of a pinion 7 S is a rack 81,which slides vertically in guides formed on the block or frame 7 O. Thisrack carries an isosceles triangle 82 on the side opposite said pinion,the perpendicular bisecting line of which is at right angles to the lineof travel of said rack 81. More or less of the transverse motion of theeccentric-rod 45 is transmitted to this rack by means of a pin 83,provided with a hub 84, sliding on a square or feathered pin 85,projecting inwardly from said eccentric-rod, the degree of motiondepending on the position of the pin 83 with respect to the apex andbase of the triangle 82, as is obvious.

It will be readily understood that the abovedescribed mechanism foroperating the cutoff valves is automatic in its action, and that byutilizing the transverse motion of the eccentric-rod no extra parts areor need be introduced, as the movement of said eccentric-rodapproximates closely to that of the high pressure piston, the transversemotion of said eccen trio-rod being peculiarly adapted to the use towhich it is put from the fact that it is the lap of the valve in advanceof the said piston. A movement of five thirtyseconds of an inch of thecut-off valve gives a large clear openin As the ports of the cutoffmechanism take steam from both sides, as shown by the arrows in Fig. 6,the valve is required to travel only one-half the width of the port toopen or close the same.

In the present instance the cut-01f port is practically twenty-six feetlong, and a movement of five thirty-seconds of an inch gives forty-eightsquare inches of opening. The throw of the eccentric 74 is two inches.The diameter of the pitchcircle of the segment of a pinion 78 is threeinches, so that obviously a movement of one-fourth of an inch in therack 81 closes the cut-off valve. The pin S5 is located at such a pointin the eccentric-rod 45 as will give a positive motion, and at the sametime will not render the connections 73 and 84 too cumbersome. In thepresent case the main eccentric 100 has a throw of three and one-halfinches, and the pin 85 is placed where it will have a vertical movementof two and one-half inches. Hence the pin 83 has the same verticalmovement, and it therefore takes an angular advance of thirty-fivedegrees of the main eccentric to close the cutoff valve.

The triangle 82, herein above described, has a width at its basesufficient to allow the pin 83 to have a play equal to its verticaltravel less the movement necessary to close the cutoff valve, which inthis case is two and onefourth inches. At the apex of this triangle saidpin fits closely to the sides of the latter.

The operation of this cut-off will be fully understood from theforegoing, taken in connection with eccentric diagram, Fig.7. Thisdiagram islaid off with the eccentric circle full size, having adiameter of three and one-half inches,which also represents thepiston-stroke, whichistwenty-fourinches,thedivision-marks indicatinginches of the piston-stroke. The crank is represented as traveling inthe same circle as the eccentric center. The pistonvalve 32 has a lap ofseven-sixteenths of an inch and a lead of one-sixteenth of an inch,giving alinear advance of one-half inch, thus placing the eccentriccenter at the point marked 101 when the crank is on a dead-center at102. Suppose the pin 83 to be at the apex of the triangle 82. Thecut-off would commence to close when the eccentric center was at 103itslower mid-position-or before the piston reached the end of its stroke.It would close when the eccentric center had traveled up thirty-fivedegrees from said mid-position or to the point marked 110, at whichtime-the crank would be at 104 and the piston at 105. Steam would thushave followed the piston only three-fourths of an inch. Supposing thepin to be at the base of the triangle 82, the cut-off would remain openuntil said pin had traveled across to the opposite side of the triangle,or until the eccentric center had reached the point marked 106,thirty-five degrees below 107,which designates the upper mid-position ofthe eccentric center,'and the said cut-oft would be closed as theeccentric center traveled from the point 106 to 107 while the crank istravelin g from the point marked 108 to 109. Valve 32 cuts off when thecrank is at 109 and the.

piston at 110. Thus steam would now have followed the piston twenty-twoinches. It is obvious that by moving pin 83 from one end of the triangleto the other the cut-off can be made to take place at any point betweenthree-fourths of an inch and twentytwo inches. It is further obviousthat in no case does the piston travel more than two and onehalf inchesduring the cut-off movement, which is practically instantaneous.

The slide-pin S3 is connected to an angle lever 86, which is pivoted tothe bracket 72 by means of a rod 88, having ball-joints. The shorthorizontal member of this angle-lever is connected to a governor 89,which may be of the ordinary and well-known construction and which issituated upon the bracket 72. When this pin 83 is disengaged from thesides of the triangle 82, the slightest force exerted upon it will besufficient to cause it to slide on the pin 85, thus rendering itextremelysensitive and capable of responding to the slightest change ofspeed. When the pin 83 engages the sides of the triangle 82, it binds onthis feathered pin 85, and further movement of the pin 83 will beprevented thereby. The

eccentric crank or cam is made sufficiently large, and there issufficient friction between it and the box or frame of the automaticcut-off gear to prevent any movement of it by the force applied to 84:-As before stated, the rod 88 has a balland-socket connection with theangle-lever 86 and sliding pin 83, which serves to accommodate thecircular motion of this rod 88 toward the eccentricrod 45. As said rod88 describes an are, it causes a slight oscillation of the angle-lever86, which oscillation would disturb the action of the governors. Toovercome this disadvantage and to permit the governor to operate whilethe pin 83 is engaged a double-act- &:c., is not changed by thevariation of cutoff; During the movement of the cut-off valve 53it isexposed to full steam-pressure on each of its sides, and it willtherefore be perfectly balanced. The combined area of the cutoff portsbeing greater than that of the steam ports the current of steam throughsaid outofi ports during admission is very slight, and what there isacts in the direction in which they are to move. Then the cut-off valvecloses, expansion begins both in the slidevalve in the rear steam-chestand in the highpressure cylinder, so that the pressureoutside is greaterthan on the inside, and the cutoff valve will be held firmly to its seatuntil said slide-valve closes the ports leading to the high-pressurecylinder. The power required to operate said cut-oft valve is thereforevery slight and its action is certain.

In Figs. 8 and 9 is exhibited the construction in which the cut-offmechanism is applied to common slide-valves, Fig. 9 being an automaticand Fig. 8 a permanent cut-off. Referring first to Fig. 9, it will beobserved that the bars between the cut-off ports 54 are located outsideand that the cut-off valves are connected by means of distance-bolts158, which are similar to the connecting-rod 43, Fig. 2, on the sides ofthe valve 32. The hollow valve-rod 57 is slotted to receive andaccoinmodate a key 159, which passes through the cut-01f rod and the hubon the cut-off. This key serves to couple the cut-off rod to said hub,in order that it will be able to work the cut-off valve. It is operatedby gear similar to that already described in connection with the valve32. In the construction shown in Fig. 8 the bars 55 between the cut-offports are located inside instead of outside, as invthe otherconstructions, and the cut-off valves 53 are connected together byasleeve 161,through which the valve-rod passes, the said valve-rod beingsecured by a set-screw 160. It acts as a valve-yoke, moving up to thecut-off ports, alternately cutting off steam and then shoving the valvealong before it. The first return movement of the valve-rod closes thecut-off whichever way it may be moving.

I do not wish to be understood as limiting myself to the preciseconstruction herein set forth, as many modifications thereof willsuggest themselves to persons skilled in the art. For example, thetriangle 82 could be secured directly to the pinion 78, thus dispensingwith the vertically-sliding rack 81; but such construction would beobjectionable, in that the triangle would have a rolling sliding motionon the pin 83. The are described by the pin is so short that it ispractically straight, so that it substantially coincides with the saidrack in its vertical movement, and the contact of pin 83 and thetriangle 82 is positive.

It is also obvious that the slip-joint 77 can be of many forms andplaced anywhere between the triangle and the valve-stems. Again in asingle-cylinder engine with a common slide valve provided with acut-off, as modified in Figs. 8 and 9, the steam-chest could be placedon one side, as is commonly done, and the hollow stem 57 and cut-oilstem extending therethrough could lead directly to the automatic deviceand the rocker (shown in Fig. 5) be dispensed with.

It will be understood that the only use of the rockerand accessories isto oltset the motion of the eccentric and automatic device in enginesconstructed to require it. There are also many ways of coupling thehollow stem 57 and the cut-off stem extending thereth rough to thevalves besides those shown. It is also obvious that the triangle 82 andsliding pin 83 can be of many forms and arranged in many different wayswithout materially altering the principle.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. In a steam-engine, the combination of a cylinder, a piston andpiston-rod operating therein, a steam-chest communicating with saidcylinder, a slide-valve operating in said steam-chest and having a wallperpendicular to its line of travel and provided with ports to admitsteam into the slide-valve, a cut-ott valve of similar form to said Walland adapted to close the ports of the latter, and mechanism foroperating said valves.

2. In a steam-engine, the combination of a cylinder, a piston andpiston-rod operating therein, a steam-chest communicating therewith, aslide-valve operating in said steamchest and controlling the entrance ofsteam to the cylinder, a cut-ofl? valve controlling the entrance ofsteam to the slide-valve, suitable connections between the latter andthe eccentric-rod of the engine, an auxiliary eccentricrod for operatingthe cut-oil valve, an eccentric for said rod, and suitable connectio11sbetween said eccentric and the main eccentricrod of the engine, wherebythe transverse movement of the latter actuates the eccentric and shiftsthe cut-oil.

3. In a steam-engine, the combination of a cylinder, a piston andpistonrod operating therein, a steam-chest communicating therewith, aslide-valve operating in said steamchest and controlling the entrance ofsteam to the cylinder, a cut-off valve controlling the entrance of steamto the slide-valve, suitable connections between the latter and theeccentric-rod of the engine, an auxiliary eccentricrod for operating thecut-01f, an eccentric for said rod having an extension in the form of afrustum of a cone, a pinion cupped to fit said extension andspring-actuated to have frictional contact therewith, a rack engagingsaid pinion, and suitable connections between said rack and the maineccentric-rod of the engine, whereby the transverse movement of thelatter actuates the said rack and consequently the pinion and eccentricand thereby the auxiliary eccentric-rod and cut-01f valve.

4. In a steam-engine, the combination of a cylinder, a piston andpiston-rod operating therein, a steam-chest communicating therewith, aslide-valve operating in said steamchest and controlling the entrance ofsteam to the cylinder, a cut-elf valve controlling the entrance of steamto the slide-valve, suitable connection between the latter and theeccentric-rod of the engine, an auxiliary eccentricrod for operating thecut-elf valve, an eccentric for said rod having an extension in the formof a frustnm of a cone, a pinion cupped to fit said extension andspring-actuated to have frictional contact therewith, a rack e11- gagingsaid pinion and having a triangular frame, and a pin engaging the latterand connected to the main eccentric-rod of the engine, whereby thetransverse movement of the latter actuates the rack and consequently thepinion and eccentric and thereby the auxiliary eccentric-rod and cut-oilvalve.

5. In a steam-engine, the combination of a cylinder, a piston andpiston-rod operating therein, a steam-chest communicating therewith, aslide-valve operating in said steamchest and controlling the entrance ofsteam to the cylinder, a cut-oil? valve controlling the entrance ofsteam to the slide-valve, suitable connections between the latter andthe eccentric-rod of the engine, an auxiliary eccentricrod for operatingthe cut-cit, an eccentric for said rod having an extension in the formof a frustum of a cone, a pinion cupped to fit said extension andspring-actuated to have frictional contact therewith, a rack engagingsaid pinion and having an isosceles triangle, a pin secured to the maineccentric-rod of the engine and projecting therefrom, and a sec- 0nd pinmounted on said first pin and engagin g said isosceles triangle, for thepurpose set forth.

6. In a steam-engine, the combination of a cylinder, a piston andpiston-rod operating therein, a steam-chest communicating therewith, aslide-valve operating in said steamchest and controlling the entrance ofsteam to the cylinder, a cut-oit' valve controlling the entrance ofsteam to the slide-valve, suitable connections between the latter andthe eccentric-rod of the engine, an auxiliary eccentricrod for operatingthe cut-01f, an eccentric for said rod having an extension in the formof a frustum of a cone, a pinion cupped to fit said extension andspring-actuated to have frictional contact therewith, a rack engagingsaid pinion and having an isosceles triangle, a pin secured to the maineccentric-rod of the englue and projecting therefrom, a second pinmounted on said first pin and engaging said isosceles triangle, andsuitable connections between the said second pin and the governor of theengine.

7. In a steam-engine, the combination of a triangle orits equivalentmounted on a block connected to and. moving in unison with the purposeof operating the cut-off variably, subro valve or eccentric-rod andconnected to the stantially as shown and described. cut-off valve by aslip-joint, and a pin sliding In testimony whereof I affix my signaturein with reference to the bisecting line of the trithe presence of twoWitnesses.

5 angle under control of an enginegovernor and having the transversemotion of the ec- EDWARD P. OOWLES.

centric-rod engaging said triangle laterally Witnesses: and transmittinga portion of the transverse A. J. GREEN,

motion of the eccentric t0 the latter for the H. L. BROWN.

